Powdery material of minute composite ceramic particles having a dual structure and a process and an apparatus producing thereof

Abstract

A powdery material of minute composite ceramic particles having a dual structure, comprising the core formed of zirconium oxide and the outer shell formed of aluminum oxide, a process for producing thereof, which comprises introducing gaseous zirconium chloride into a combustion chamber provided with a constricting section at the center part thereof and a burner at the upper part thereof, introducing gaseous aluminum chloride into the combustion chamber at the constricting section or the lower part thereof, and thermally decomposing both the thus introduced zirconium chloride and aluminum chloride by a flame from said burner under an oxidative atmosphere, and an apparatus for producing thereof.

What is claimed is: 
     
       1. A sinterable powdery material of minute composite ceramic particles of a dual structure comprising the core formed of zirconium oxide and the outer shell formed of amorphous aluminum oxide, wherein the content of zirconium oxide is 10 to 25 percent by weight and the volume percentage of monoclinic crystalline phase of said zirconium oxide to the total zirconium oxide crystalline phases is less than 50. 
     
     
       2. A powdery material according to claim 1, wherein the mean diameter of said composite ceramic particles is in the range of from 400 to 1000 Å.